Abstract: Pipe joint components such as a metallic sleeve and companion nut of a compression-type pipe coupling are externally coated with a corrosion-resistant polymeric plastic. In a preferred embodiment the coating on the female of the components extends as a flexible skirt beyond the mating end face thereof to include an internally integral annular O-ring formation. The coating on the male fitting terminates behind the threads thereof in an annular ramp or boss adapted in assembly to be engaged by the O-ring coating formation of the female fitting. Cooperation of the engaging O-ring and ramp effects a moisture seal relation thereat.